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Commit 82fa3c77 authored by KY Srinivasan's avatar KY Srinivasan Committed by David S. Miller
Browse files

hv_netvsc: Use the xmit_more skb flag to optimize signaling the host 



Based on the information given to this driver (via the xmit_more skb flag),
we can defer signaling the host if more packets are on the way. This will help
make the host more efficient since it can potentially process a larger batch of
packets. Implement this optimization.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9eea9222

drivers/net/hyperv/netvsc.c

+27 −16
Original line number Diff line number Diff line
@@ -743,6 +743,7 @@ static inline int netvsc_send_pkt( 
	u64 req_id;

	int ret;

	struct hv_page_buffer *pgbuf;

	u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);



	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;

	if (packet->is_data_pkt) {
@@ -769,32 +770,42 @@ static inline int netvsc_send_pkt( 
	if (out_channel->rescind)

		return -ENODEV;



	/*

	 * It is possible that once we successfully place this packet

	 * on the ringbuffer, we may stop the queue. In that case, we want

	 * to notify the host independent of the xmit_more flag. We don't

	 * need to be precise here; in the worst case we may signal the host

	 * unnecessarily.

	 */

	if (ring_avail < (RING_AVAIL_PERCENT_LOWATER + 1))

		packet->xmit_more = false;



	if (packet->page_buf_cnt) {

		pgbuf = packet->cp_partial ? packet->page_buf +

			packet->rmsg_pgcnt : packet->page_buf;

		ret = vmbus_sendpacket_pagebuffer(out_channel,

		ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,

						      pgbuf,

						      packet->page_buf_cnt,

						      &nvmsg,

						      sizeof(struct nvsp_message),

						  req_id);

						      req_id,

						      VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,

						      !packet->xmit_more);

	} else {

		ret = vmbus_sendpacket(

				out_channel, &nvmsg,

		ret = vmbus_sendpacket_ctl(out_channel, &nvmsg,

					   sizeof(struct nvsp_message),

					   req_id,

					   VM_PKT_DATA_INBAND,

				VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

					   VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,

					   !packet->xmit_more);

	}



	if (ret == 0) {

		atomic_inc(&net_device->num_outstanding_sends);

		atomic_inc(&net_device->queue_sends[q_idx]);



		if (hv_ringbuf_avail_percent(&out_channel->outbound) <

			RING_AVAIL_PERCENT_LOWATER) {

			netif_tx_stop_queue(netdev_get_tx_queue(

					    ndev, q_idx));

		if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {

			netif_tx_stop_queue(netdev_get_tx_queue(ndev, q_idx));



			if (atomic_read(&net_device->

				queue_sends[q_idx]) < 1)